Method for Mechanical Sensing Utilizing Controlled Current

ABSTRACT

A method for sensing. The method includes the steps of transmitting mechanical forces to one or more printed mechanical sensing elements. There is the step of sending prompting signals associated with the mechanical forces to a computer in communication with one or more printed diodes and the one or more printed mechanical sensing elements. There is the step of reconstructing with the computer the mechanical forces that were applied to the one or more printed mechanical sensing elements. An apparatus for sensing. The apparatus includes a computer. The apparatus includes one or more printed electronic diodes and printed mechanical sensing elements connected to the computer, the one or more printed electronic diodes detect mechanical signals applied to the one or more mechanical-sensing elements and that provide corresponding values to the computer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 13/943,593filed Jul. 16, 2013, now U.S. Pat. No. 10,527,505, which is anonprovisional of U.S. provisional application Ser. No. 61/676,720 filedon Jul. 27, 2012, all of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

This section is intended to introduce the reader to various aspects ofthe art that may be related to various aspects of the present invention.The following discussion is intended to provide information tofacilitate a better understanding of the present invention. Accordingly,it should be understood that statements in the following discussion areto be read in this light, and not as admissions of prior art.

With recent advances in thin-film transistors and organic/inorganicsemiconductor inks, printed electronic techniques have seen increaseddevelopment and usage. It is now possible to create transistors, lightemitting diodes and flexible circuits using these printed electronictechniques, such as screen-printing, ink-jet and gravure. Printedelectronic techniques provide the potential for low cost, lightweightand flexible electronics.

This invention formulates a means to concurrently utilize two printedelectronic components, a printed sensing element 203 and a printed diode208, in order to provide current flow control to a mechanical forcesensor or sensors, and is manufactured using printed electronictechniques that allow for thin, flexible, low cost production.

Different embodiments of the printed sensing element 203 have been inuse for several decades. A printed sensing element 203 with forcesensitive resistive material 24, for instance, has been in use since the1970s. An issue with using a PSE 203 in a larger circuit or usingseveral PSE 203 connected in a network is that current can flow in bothdirections through a sensing element, often creating alternate circuitsthat create false positive 224 or drain 223 cross-talk 222. In thesesituations, the crosstalk causes variability to the values of the signalbeing read from similar mechanical forces being applied to the PSE 203.To address this, the PSE 203 either had to be isolated into singleelement circuits or computer algorithms were used to compensate for theerrors. A non-printed diode could be placed on a printed circuit board 8before each PSE 203 but this would require networks of PSE 203 to returnto the circuit board between each PSE 203 and would be impractical withan active sensing array 20 of PSE 203.

In prior art, a two-dimensional grid of PSE 203 forms an active sensingarray of elements (ASA) 20. Tekscan, for instance, has created an ASA 20using FSR material 24 that provides a time-varying pressure image.

Printed diodes are a relatively recent development, with continuedgrowth in its commercial use over the past five years (2007-2012). Theprimary uses in the industry have been for organic light-emitting diode(OLED) displays and for flexible electronics. Breakthroughs in organicand inorganic semiconductors have made it possible to print electroniccircuits on flexible substrates using printed electronic techniques.

This invention solves the cross talk 222 of the PSE 203 by depositing aprinted diode 208 in contact with each PSE 203 to form a printeddiode-sensing element (PDSE) 211. By using printed electronic techniquesfor the sensing element and the diode, one or more PDSE can be made thatcontrol the flow of current and can be made on a thin, low-cost,flexible substrate.

BRIEF SUMMARY OF THE INVENTION

This invention describes the printed-diode sensing element (PDSE) 211,which combines the mechanical force detection of a printed sensingelement (PSE) 203 with the electrical current control of a printed diode208 using printed electronic manufacturing techniques. A printed diode208 is formed from one or more layers of doped semiconductor 205 and/orconductive material 201 printed in contact. Embodiments could utilizes,printed diode types such as an MS Junction 209 and P-N Junction 210. AMS Junction 209 is formed when an n-type semiconductor 207 is printed incontact with a conductive material 201. A P-N Junction 210 is formedwhen an n-type semiconductor 207 is printed in contact with a p-typesemiconductor 206. A printed sensing element (PSE) 203 is made from twolayers of printed conductive material 201 and one or more layers ofmechanical sensing material (MSM) 202, which is printed between thelayers of conductive material 201. An MSM responds to mechanical forces,changing the electrical properties of the PSE 203. MSM embodiments caninclude force sensitive resistor (FSR) material 23, piezoelectricmaterial 204, and dielectric material 219. PSE layers are printed on oneor more non-conductive surface substrates 22 to form sensor surfacesheets 21. When PSE layers are printed on more than one sensor surfacesheet 21, the sensor surface sheets are brought into mutual contact toform a PSE. Otherwise, the PSE is formed on the single sensor surfacesheet 21. In the PDSE 211, a printed diode 208 is deposited between oneside of conductive material 201 and the MSM 202 layers. The PDSE 211 canbe designed as a single element, a network of elements or an activesensing array (ASA) 20. An ASA 20 is a grid of conductive traces 23 witha PSE 203 or PDSE 211 at the conductive trace intersections. The printeddiode 208 and MSM 202 of the PDSE 211 can be deposited using printedelectronic methods, including screen-printing, flexography, and inkjet.

The PDSE provides several advantages over a PSE 203. With the PDSE 211,there is no cross talk 222 through false positive 224 or drain 223 whenconnected to an ASA 20 or a network of elements. In an ASA 20 with thePDSE 211, for instance, current can only flow from output conductivetraces 220 to input conductive traces 221, preventing alternate circuitsfrom forming. As a result, the PDSE 211 does not require additionalhardware or software to compensate for information that would be lost orgained from cross talk 222 drain 223 or false positive 224.

The present invention pertains to a sensor. The sensor comprises one ormore printed mechanical sensing elements that detect mechanical forcesapplied to an element. The sensor comprises one or more printed diodeswhich are in contact with the one or more mechanical sensing elementsand which control flow of electrical current to and from the one or moreprinted mechanical sensing elements. The sensor comprises a computer incommunication with the printed mechanical-sensing elements which causesprompting signals to be sent to the one or more printed mechanicalsensing elements and which reconstructs data signals received from theone or more printed mechanical-sensing elements through the one or moreprinted diodes.

The present invention pertains to a method for sensing. The methodcomprises the steps of transmitting mechanical forces to one or moreprinted mechanical sensing elements. There is the step of sendingprompting signals associated with the mechanical forces to a computer incommunication with one or more printed diodes and the one or moreprinted mechanical sensing elements. There is the step of reconstructingwith the computer the mechanical forces that were applied to the one ormore printed mechanical sensing elements.

The present invention pertains to an apparatus for sensing. Theapparatus comprises a computer. The apparatus comprises one or moreprinted electronic diodes and printed mechanical sensing elementsconnected to the computer, the one or more printed electronic diodesdetect mechanical signals applied to the one or more mechanical-sensingelements and that provide corresponding values to the computer.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1A shows a side view of the Single-MSM M-S Sensing Element (SMSSE)212.

FIG. 1B shows a top view of the Single-MSM M-S Sensing Element (SMSSE)212.

FIG. 2A shows a side view of the Single-MSM P-N Sensing Element (SPNSE)213.

FIG. 2B shows a top view of the Single-MSM P-N Sensing Element (SPNSE)213.

FIG. 3A shows a side view of the Double-MSM M-S Sensing Element (DMSSE)214.

FIG. 3B shows a top view of the Double-MSM M-S Sensing Element (DMSSE)214.

FIG. 4A shows a side view of the Double-MSM P-N Sensing Element (DPNSE)215.

FIG. 4B shows a top view of the Double-MSM P-N Sensing Element (DPNSE)215.

FIG. 5 shows the PDSE 211 network schematic used to control the flow ofelectric signals from an output voltage 229 to an input voltage 230.

FIG. 6A shows a schematic of an ASA 20 with PDSE 211, where the top-leftPDSE 211 is being scanned and non-active conductive traces 23 are set toground.

FIG. 6B shows a schematic an active sensing array 20 with PDSE 211,where the top-left PDSE 211 is being scanned and non-active conductivetraces 23 are connected to high impedance or are floating.

FIG. 7 shows a schematic of an active sensing array 20 where thetop-left PDSE 211 is being scanned and non-active conductive traces 23are connected to high impedance or are floating by using multiplexers225 and demultiplexer 226.

FIG. 8A shows an example of voltage drain 223 cross talk 222.

FIG. 8B shows an example of false positive 224 cross talk 222.

FIG. 9 shows a schematic of an ASA 20 with PDSE 211 where outputconductive traces 220 connected to Digital I/O pins 82 of aMicrocontroller 5 and input conductive traces 221 connected to ADC pins83 of a Microcontroller 5.

FIG. 10 shows a schematic of an ASA 20 with PDSE 211 where outputconductive traces 220 connected to Digital I/O pins 82 of aMicrocontroller 5 and input conductive traces 221 connected tooperational amplifiers 227 that are connected to ADC pins 83 of aMicrocontroller 5.

FIG. 11 shows a schematic of an ASA 20 with PDSE 211 where operationalamplifiers 227, multiplexer 225 and demultiplexer 226 are used forscanning the active sensing array 20 by measuring voltage after the PDSE211.

FIG. 12 shows a schematic of an ASA 20 with PDSE 211 where operationalamplifiers 227, a multiplexer 225, an demultiplexer 226 and a currentshunt monitor 228 are used for scanning the active sensing array 20 bymeasuring current after the PDSE 211.

FIG. 13 shows an embodiment of a non-conductive surface substrate 22with conductive material 201 and printed material 200, like MSM 202 ordoped semiconductor 205.

FIG. 14 shows the alignment of two non-conductive surfaces to create anASA 20.

FIG. 15 shows an ASA 20.

FIG. 16A shows a side view of the One-Sheet Single-MSM P-N SensingElement (OSPNSE) 216.

FIG. 16B shows a top view of the One-Sheet Single-MSM P-N SensingElement (OSPNSE) 216.

FIG. 17A shows a PDSE 211 and printed circuit board 8 connected to acomputer 3 with a computer display 6.

FIG. 17B shows an ASA 20 and printed circuit board 8 connected to acomputer 3 with a computer display 6.

FIG. 18 shows a single PDSE 211 with a printed diode 208 and mechanicalsensing material 203 connected to an output voltage 229 and an inputvoltage 230.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein like reference numerals refer tosimilar or identical parts throughout the several views, and morespecifically to FIG. 1A thereof, there is shown a sensor. The sensorcomprises one or more printed mechanical sensing elements that detectmechanical forces applied to an element. The sensor comprises one ormore printed diodes which are in contact with the one or more mechanicalsensing elements and which control flow of electrical current to andfrom the one or more printed mechanical sensing elements. The sensorcomprises a computer in communication with the printedmechanical-sensing elements which causes prompting signals to be sent tothe one or more printed mechanical sensing elements and whichreconstructs data signals received from the one or more printedmechanical-sensing elements through the one or more printed diodes.

The computer may be in communication with the one or more printedmechanical-sensing elements by conductive material which causes theprompting signals to be sent to the one or more printed mechanicalsensing elements and which reconstructs the data signals received by theconductive material from the one or more printed mechanical-sensingelements through the one or more printed diodes. The conductive materialmay form a grid that defines intersections, whereby each intersectioncontains a printed mechanical sensing element in contact with a printeddiode.

Each printed mechanical sensing element may include a force sensitivevariable resistor. Each printed mechanical sensing element may includeforce sensitive resistive ink.

The grid and the printed mechanical sensing elements and the printeddiodes may. form a mechanical sensing layer.

The present invention pertains to a method for sensing. The methodcomprises the steps of transmitting mechanical forces to one or moreprinted mechanical sensing elements. There is the step of sendingprompting signals associated with the mechanical forces to a computer incommunication with one or more printed diodes and the one or moreprinted mechanical sensing elements. There is the step of reconstructingwith the computer the mechanical forces that were applied to the one ormore printed mechanical sensing elements.

The present invention pertains to an apparatus for sensing. Theapparatus comprises a computer. The apparatus comprises one or moreprinted electronic diodes and printed mechanical sensing elementsconnected to the computer, the one or more printed electronic diodesdetect mechanical signals applied to the one or more mechanical-sensingelements and that provide corresponding values to the computer.

List of All Components

A Printed Diode Sensing Element (PDSE) 211 consisting of:

-   -   Printed Sensing Element (PSE) 203        -   Nonconductive surface substrate 22        -   Conductive material 201        -   Mechanical Sensing Material (MSM) 202    -   Printed Diode 208        -   Technique: P-N Junction 210            -   P-type semiconductor 206            -   N-type semiconductor 207        -   Technique: M-S Junction 209            -   N-type semiconductor 207

Scanning Electronics consisting of:

-   -   Microcontroller 5 which contains:        -   Analog Digital Converter 83        -   Digital I/O Pins 82    -   Technique: Reading Voltage        -   Operational Amplifiers 227        -   Multiplexer 225        -   Demultiplexer 226    -   Technique: Reading Current        -   Multiplexer 225        -   Demultiplexer 226        -   Current Shunt Monitor 228        -   Operational Amplifiers 227

Glossary of terms and Description of Components

Printed Material 200: a material that can be deposited using printedelectronic techniques, like screen-printing, ink jet and gravure.

Conductive Material 201: a printed material 200 that conductselectricity.

Non-Conductive Surface Substrate 22: an insulator material that resistselectric charge and provides a base for sensing element materials.

Sensor Surface Sheet 21: a non-conductive surface substrate 22 withconductive material 201, MSM 202 and/or doped semiconductors 205 printedon the non-conductive surface substrate.

Mechanical Sensing Material (MSM) 202: a printed material 200, whichresponds to mechanical forces.

Printed Sensing Element (PSE) 203: made from two layers of printedconductive material 201 and one or more layers of mechanical sensingmaterial (MSM) 202, which is printed between the layers of conductivematerial 201. The PSE layers are printed on one or two non-conductivesensor surface sheets 22 so that the layers are brought into contact.

Force Sensitive Resistor (FSR) Material 24: a printed semi-conductivevariable resistive material that reduces in resistance when force isapplied.

Piezoelectric Material 204: a printed material that generates chargewhen mechanical force is applied to it. It is also possible to applyelectrical signals to some piezoelectric materials to deform thematerial.

Doped Semiconductor 205: a semiconductor material that has impuritiesintroduced to it in order to alter its electrical properties.

P-Type Semiconductor 206: a doped semiconductor that accepts weaklybound electrons.

N-Type Semiconductor 207: a doped semiconductor that has negativeelectron charge carriers.

Printed Diode 208: a printed electronic made from layers of dopedsemiconductor 205 and/or conductive material 201 that allow current topass in one direction.

Metal-Semiconductor (M-S) Junction 209: one type of the printed diode208 where an n-type semiconductor 207 is printed over conductivematerial 201 (or conductive trace) to create a metal-semiconductorjunction, also called an Schottky barrier.

P-N Junction 210: one type of the printed diode 208 where an n-typedoped semiconductor 207 is printed over a p-type doped semiconductor205, which is printed over a conductive material 201 (or conductivetrace 23) to create a P-N junction.

Printed Diode Sensing Element (PDSE) 211: combines the mechanicalsensing qualities of a printed sensing element 203 with the currentcontrolling properties of a printed diode 208.

Single-MSM M-S Sensing Element (SMSSE) 212: a single-sided MSM 202 M-SJunction 209 PDSE 211.

Single-MSM P-N Sensing Element (SPNSE) 213: a single-sided MSM 202 P-NJunction 210 PDSE 211.

Double-MSM M-S Sensing Element (DMSSE) 214: a double-sided MSM 202 M-SJunction 209 PDSE 211.

Double-MSM P-N Sensing Element (DPNSE) 215: a double-sided MSM 202 P-NJunction 210 PDSE 211.

One-Sheet Single-MSM P-N Sensing Element (OSPNSE) 216: a one-sheetsingle-sided MSM 202 P-N Junction 210 PDSE 211.

Dielectric Material 219: an insulator material that can become polarizedand is used in resistive and capacitive sensors.

Conductive Traces 23: conductive material 201 that is used to connectone or more PSE 203, provide a pad of conductive material for printingMSM 203 and/or doped semiconductor 205, and/or connect to a circuitboard 8.

Output Conductive Traces 220: a conductive trace 23 of an active sensingarray 20 that is supplied with a voltage from the printed circuit board8.

Input Conductive Traces 221: a conductive trace 23 of an active sensingarray 20 that is the input to the printed circuit board 8 that isconnected to the ADC 83.

Active Sensing Array 20: a grid of conductive traces 23 with a printedsensing element 203 or PDSE 211 at each conductive trace intersection.

Cross-Talk 222: a phenomenon found with PSE 203 without printed diodes208 where unintended circuits are formed due to a lack of currentcontrol, which cause the input voltage and/or current to misrepresentthe value of the printed sensing elements 203.

Drain 223: a form of cross talk where, after passing through a PSE 203,parallel circuits to the ADC 83 are created to ground, which result in alower voltage and current on the ADC 83 being read. In an ASA 20 withoutprinted diodes 208, alternate paths can be created if output or inputtraces are set to ground and multiple PSE 203 allow current to flowthrough them.

False Positive 224: a form of cross talk where unintended circuits arecreated between PSE 203 without printed diodes 208 to the ADC 83,resulting in increased voltage being read by the ADC 83. The increasedvoltage results in a value being read on a sensing element that is notsending signals.

Multiplexer 225: an integrated circuit that sends one of severalelectrical input signals that is connected to the integrated circuit.

Demultiplexer 226: an integrated circuit that sends a single signal downone of several outputs.

Operational Amplifier 227: an integrated circuit with a differentialinput and an output. Operational amplifiers can be used for a variety ofpurposes, including amplifying analog signals, setting a consistentanalog voltage source value, stabilizing analog signals and measuringcurrent.

Analog Digital Converter (ADC) 83: an integrated circuit that convertsanalog electrical signals to a numerical digital value.

Current Shunt Monitor 228: a type of operational amplifier 227 that isdesigned to measure current in a circuit by measuring voltage differenceacross a resistor.

Output Voltage 229: the voltage that is supplied from the printedcircuit board 8.

Input Voltage 230: voltage that comes into the printed circuit board 8.

General Purpose of Each Layer: Printed Diode Sensing Elements

FIGS. 1A, 2A, 3A, 4A, and 16A show side views of various embodiments ofthe PDSE 211, the Single-MSM M-S Sensing Element (SMSSE) 212, Single-MSMP-N Sensing Element (SPNSE) 213, Double-MSM M-S Sensing Element (DMSSE)214, Double-MSM P-N Sensing Element (DPNSE) 215 and One-Sheet Single-MSMP-N Sensing Element (OSPNSE) 216 respectively. In each PDSE 211embodiment, a printed diode is deposited between one side of conductivematerial 201 and the MSM 202. The printed diode is formed from one ormore layers of doped semiconductor 205 and/or conductive material 201.In each of the two sensor surface sheet 21 embodiments, seen in FIGS.1A, 2A, 3A, 4A, the corresponding outer most layers of the PDSE 211 oneach respective sheet 21 are aligned and in contact when the two surfacesheets 21 are placed together.

The Single-MSM M-S Sensing Element (SMSSE) in FIG. 1A has MSM 202 overconductive material 201 on a non-conductive surface substrate 22 on onesensor surface sheet 21 and n-type semiconductor 207 over conductivematerial 201 on a non-conductive surface substrate 22 on the othersensor surface sheet 21. The SMSSE forms a M-S junction 209 printeddiode and a single layer of MSM 202.

The Single-MSM P-N Sensing Element (SPNSE) in FIG. 2A has MSM 202 overconductive material 201 on a non-conductive surface substrate 22 on onesensor surface sheet 21 and n-type semiconductor 207 over p-typesemiconductor 206 over conductive material 201 on a non-conductivesurface substrate 22 on the other sensor surface sheet 21. The SPNSEforms a P-N junction 210 printed diode and has one layer of MSM 202.

The Double-MSM M-S Sensing Element (DMSSE) in FIG. 3A has MSM 202 overconductive material 201 on a non-conductive surface substrate 22 on onesensor surface sheet 21 and MSM 202 over n-type semiconductor 207 overconductive material 201 on a non-conductive surface substrate 22 on theother sensor surface sheet 21. The DMSSE forms a M-S junction 207printed diode and has two layers of MSM 202.

The Double-MSM P-N Sensing Element (DPNSE) in FIG. 4A has MSM 202 overconductive material 201 on a non-conductive surface substrate 22 on onesensor surface sheet 21 and MSM 202 over n-type semiconductor 207 overp-type semiconductor 206 over conductive material 201 on anon-conductive surface substrate 22 on the other sensor surface sheet21. The DPNSE forms a P-N junction 210 printed diode and has two layersof MSM 202.

The One-Sheet Single-MSM P-N Sensing Element (OSPNSE) in FIG. 16A hasall the PSE 203 and printed diode layers on one sensor surface sheet 21.In this embodiment, conductive material 201, MSM 202, n-typesemiconductor 207, p-type semiconductor 206, and conductive material 201are printed in that order over a non-conductive surface substrate 22.The OSPNSE forms a P-N junction 210 printed diode and has one layer ofMSM 202. In an alternate embodiment of the OSPNSE the materials could beprinted in the opposite order.

FIGS. 1B, 2B, 3B, 4B, and 16B show top view and alignment of the SMSSE212, SPNSE 213, DMSSE 214, DPNSE 215 and OSPNSE 216 when the conductivematerial 201 is a conductive trace 23. Conductive traces 23 can be usedwhen wiring one or more sensing elements into a circuit, a network or anactive sensing array 20. As seen in FIGS. 1B, 2B, 3B, 4B, and 16B, therespective layers are printed with each subsequent layer becomingshorter along the direction of the conductive trace line and wider inthe direction away from the trace to promote proper contact withoutshorting the connection for the respective the layers. Additionally, insome embodiments the conductive trace line 23 is enlarged to create alarger surface area at the location of the Printed Sensing Element 203,as seen in FIG. 17.

The Step-By-Step Description of the User Experience

In one-time step, mechanical forces are applied to a PDSE 211. Theprinted circuit board scans the PDSE 211 and sends the valuescorresponding to the detected mechanical forces to the computer 3.

On the computer 3, resulting values of the mechanical forces are storedin a region of computer memory. Software on the computer can store thevalues to secondary storage such as a hard disk, to display an imagerepresentation of the values on a computer display 6, perform analysis,or used for other purposes.

On the next time step, the above process is repeated, and so on for eachsuccessive time step.

The types of mechanical forces detected correspond to the type ofmechanical sensing material 202 in the PDSE 211. For example, in anembodiment where FSR material 24 is the MSM 202, then the amount offorce compressing the PSE 203 is detected.

Step By Step Description of Internal Workings Printed Circuit Board toOutput Conductive Traces

In this step, a voltage is supplied to an output conductive trace 220 bya printed circuit board 8.

For a single PDSE 211 embodiment, an output voltage 229 is applied tothe conductive trace 23 by a microcontroller 5, an operational amplifier227 or another integrated circuit that can create the voltage. FIG. 18shows a single PDSE 211 connected to an output voltage.

A network of PDSE 211 can be connected to one or more output voltage229. FIG. 5 shows an embodiment of a PDSE 211 network with two outputvoltages 229, each connected to two PDSEs 211.

For an active sensing array 20 embodiment with PDSE 211 connected to theprinted circuit board 8, there are several means for switching theoutput conductive trace 220 that is powered are available. In the oneembodiment, each output conductive trace 220 is connected to a digitalI/O pin 82 on a microcontroller 5 that can switch between an outputvoltage and ground, as seen in FIGS. 9 and 10. In one implementation,each output conductive trace 220 was connected to a PIC24HJ256GP610digital I/O 82 pin that supply 3.3V. In another embodiment, a singleoutput voltage, created by a digital I/O 82, operational amplifier 227,or other integrated circuit, is connected to a demultiplexer 226 thatgives a one output conductive trace 220 a voltage, while the otheroutput conductive traces 220 are floating, as seen in FIGS. 11 and 12.Using a demultiplexer 226 allows for the same output voltage to be usedfor each output conductive trace 220. Additionally, a single outputvoltage can be tuned more easily. A reduced voltage means would meanthat the current and power requirements for an active sensing array 20would be reduced. In one implementation, a 3.3V was reduced to 1V byresisters in series that was fed into an operational amplifier 227voltage follower circuit. The voltage of the operational amplifier 227became the output for a demultiplexer 226, which supplied voltage to oneoutput conductive trace 220 while the rest of the output conductivetraces 220 were floating.

Printed Diode Sensing Elements

In this step, current passes from an output conductive trace 220 througha PDSE 211 to an input conductive trace 221 if the following conditionsare met: a voltage difference exists between conductive traces 23,current is allowed to pass through the printed diode in the direction ofthe voltage difference, and mechanical forces applied to the printedsensing element 203 cause current to flow through the PSE. With a singlePDSE 211, the voltage placed on the output conducting trace 220 cancause current through the PSE 203 if the input conducting trace 221 ifthere is a voltage difference, the MSM 202 is activated, and the currentcan pass in the direction of the voltage difference. If the PSE 203 didnot have a printed diode 208, current could flow in either directionthrough the PSE 203.

FIG. 5 shows an embodiment of a network of PDSE 211 that relies oncurrent flowing in one direction. In this figure, two signal inputs arebeing split between two signal outputs. As each PDSE 211 is activated,signal from each output voltage is being sent to its matched inputvoltage (Out1 to In1, Out1 to In2, Out2 to In1 and Out2 to In2). In aPSE 211 without printed diode 208, activating three sensing elementswould cause a false positive 224 to appear from the fourth due to falsepositive 224 cross talk 222. With the PDSE 211, current can only flowfrom the output voltage to the input voltage and no cross talk ispossible.

In an active sensing array 20 with PDSE 211, current flows from theoutput conducting lines 220 to the input conducting lines 221 if thereis a voltage difference and MSM 202 activation. Two possible forms ofthe printed diode are the M-S Junction 209 and the P-N Junction 210. TheM-S Junction 209 is created between a metal and an n-type semiconductor207 as seen in FIGS. 1 and 3. A P-N Junction is created between a p-type206 and an n-type semiconductor 207, as seen in FIGS. 2, 4 and 16.

Without diodes controlling the direction of current in the PSE 203, theactive sensing array could experience cross talk 222 drain 223 and falsepositive 224. This is in contrast to the embodiments described in thisinvention, where there is no cross talk 222 drain 223 and false positive224 in the ASA 20 or any other similar network of PDSE 211. FIG. 8Ashows an embodiment of drain cross talk in the active sensing array 20without printed diodes. Drain occurs when parallel circuit paths toground are made after passing though the sensing element being measuredand moves through other sensing elements. FIG. 8B shows an embodiment offalse positive cross talk in the active sensing array 20 without printeddiodes. False positives occur when alternative circuits are formed fromthe output voltage 229 to the input voltage 230 other than the intendedscanned sensing element.

A side effect of using a diode at every sensing element is there is avoltage drop when moving through the diode from the output conductivetraces to the input conductive traces. As a result, the output voltagemust overcome this voltage difference to have current pass to the inputconductive traces. Thus, in an active sensing array, applied outputvoltage is higher when printed diodes are incorporated than when theyare not.

Input Conductive Lines to Printed Circuit Board

In this step, when the input conductive line is connected to a printedcircuit board and has a path to ground or another voltage source,current can flow and either the voltage or current after the sensingelement can be read.

With a single PDSE 211, current flows from the PDSE, along theconductive trace 23 to an input voltage 230, as seen in FIG. 18, and canbe connect to a printed circuit board 8. In an embodiment where voltageis read, an analog digital converter (ADC) 83 and a resistor to groundcan be put in parallel and connected to the input conductive trace 221.The ADC in this embodiment would measure the voltage before the resistorand assign a numerical value to the voltage value depending on the rangeand settings of the ADC 83. In an embodiment where the current is beingread, a current shunt monitor 228 is placed around a resistor that isconnected to ground and the input conductive line. The current shuntmonitor 228 determines the voltage difference across the resistor causedby the current and outputs a voltage that can be read by an ADC toassign a numerical value to the current across the resistor.

In one embodiment, the printed circuit board 8 is connected to an activesensing array 20, each input conductive trace 221 is connected to a pinon a microcontroller that can switch between an ADC 83 and ground, asseen in FIG. 9. In one implementation, each output conductive trace wasconnected to a PIC24HJ256GP610 pin that could be read by an onboard ADC83.

An ADC, however, is often not flexible and is often set to a certainvoltage range. In the case of the PIC24HJ256GP610, that range was 0V to3.3V. Therefore, with the PDSE 211, the voltage drop across the printeddiode diminished the voltage range at the ADC. Additionally, MSM 202 andconductive traces 23 have some resistance, resulting in a drop involtage from a voltage source.

In another embodiment, input conductive traces 221 are connected to oneor more operational amplifiers 227, seen in FIG. 10. These formnon-inverting amplifying circuits to strengthen the voltage signal fromthe input conductive traces 221. In one implementation, each inputconductive trace 221 is connected a non-inverting operational amplifiercircuit, each of which feeds into an ADC 83 to measure voltage. Inanother implementation, each input conductive trace 221 is connected toa current shunt monitor 219 to measure current, which is connected to anADC 83.

In FIGS. 11 and 12 embodiments with multiplexers 226, a singlenon-inverting operational amplifier circuit (FIG. 11) or current shuntmonitor (FIG. 12) can be used and connected to a single ADC 83 pin. Thisremoves the need for additional ADC pins 83, does not require the ADC toswitch between pins and reduces the number operational amplifiers 227 orcurrent shunt monitors 228.

Methods to Manufacture

In the PDSE 211, all layers are deposited using printed electronictechniques such as additive techniques like screen-printing, ink-jet,stamping and gravure and subtractive techniques like etching. Printedelectronics can be printed on a variety of substrates, includingflexible plastic films. Printed electronic manufacturing techniquesfacilitate low-cost, thin, and flexible devices. To form the PDSE 211,several printed electronic techniques can be used in conjunction. Aftereach layer is printed onto the sensor surface sheet 21, the sheet isheated to evaporate or cure the material layer.

An embodiment of the ASA with PDSE is shown in FIGS. 13, 14 and 15. FIG.13 shows a single sensor surface sheet 21 with conductive traces 23,mechanical sensing material 202 and/or doped semiconductor 205. FIG. 14shows the alignment of the sensor surface sheets and FIG. 15 shows thefinal ASA 20 with a PDSE 211 at each intersection.

In one embodiment, silver conductive material 201 and FSR material 24are deposited using screen-printing and doped semiconductors of theprinted diode are deposited using ink-jet to create a DPNSE 215 ASA 20.This embodiment detects forces that bring the two sensor surface sheetstogether and compress the layers of FSR material, lowering theresistance through the PDSE 211.

In another embodiment, silver conductive material 201, piezoelectricmaterial 204 and doped semiconductor 205 are deposited usingscreen-printing on one sensor surface sheet to create a OSPNSE 215 ASA20 that creates a pressure-sensitive sensor that responds to mechanicalforces that compress the piezoelectric material. 204.

It is also possible to use printed electronic techniques to printorganic LEDs 231 with one or more PDSE 211, either as the Printed Diode208 or an alternate circuit. An OLED 231 is a type of printed diode thatemits visible light when current flows through the diode. As a result,an OLED 231 can be used as the printed diode 208 within a PDSE 211,causing visual feedback to the mechanical forces being detected. Onesuch embodiment of the PDSE 211 using FSR 24 as the MSM and using OLED231 as the printed diode 208 would result in light emitting from theOLED when force is applied to the PDSE 211. An OLED display can also beprinted on a non-conductive surface substrate 22 with one or more PDSE211, where the PDSE and the OLED display are on separate circuits. Thisallows for an OLED display to be controlled by a microcontroller withoutinterfering with the PDSE sensing, but requires only one printedelectronic component rather than two, potentially making the combinedcomponent thinner and cheaper than the separate components.

Assembly

Using FSR material 24, organic doped semiconductors 205, silverconductive material 21 and mylar non-conductive surface substrates 22,several single PDSE were created, which formed SMSSE 212 and SPNSE 213implementations.

To begin, pads of silver conductive material 201 were screen-printed onmylar non-conductive surface substrates 22. After screen-printing thesilver, the mylar sheets were placed in an oven to evaporate solventwithin the silver conductive material. On half of the mylar sheets, twolayers of FSR material 24 were screen-printed over the conductivematerial so that the FSR material is in contact with the silverconductive material 201. After each FSR material layer, the Mylar sheetswere placed in an oven to cure the FSR material.

If a mylar sheet with conductive material and a mylar sheet withconductive and FSR material are brought together so that FSR material ofone sheet is in contact with conductive material of the other, then aPSE 203 is formed. When forces are applied to the PSE that compress theFSR material of one mylar sheet to conductive material of the othermylar sheet, the resistance between the layers of silver conductivematerial decreases.

To transform the PSE to PDSE, printed diodes 208 were deposited on themylar sheets with conductive material only. Two printed diode 208implementations were created: the M-S Junction 209 and the P-N junction210. The M-S junction 209 printed diode 208 was formed from n-typesemiconductor ink 207 deposited over the conductive material. In thisimplementation, the n-type semiconductor ink 207 was a 2% concentrationof Polyera AcivInk N2200 in a 1,2 Dichlorobenzene solution. Afterdepositing the solution using pipettes, the mylar sheets were place inan oven to evaporate the Dichlorobenzene solvent. The P-N junction 210printed diode 208 was formed from n-type semiconductor ink 207 depositedover p-type semiconductor ink 206 deposited over the conductivematerial. In this implementation, the p-type semiconductor was a 2%concentration of Polyera Activink P0400 in a 1,2 Dichlorobenzenesolution, and the n-type semiconductor ink 207 was a 2% concentration ofPolyera AcivInk N2200 in a 1,2 Dichlorobenzene solution. After eachdeposition of semiconductor ink, the mylar sheets were placed in an ovento evaporate the Dichlorobenzene solvent.

Placing the mylar sheet with semiconductor and conductive materialtogether with the mylar sheet with FSR and conductive material so thatthe semiconductor was in contact with the FSR material, resulted in PDSEbeing formed. With the M-S junction implementation, SMSSE 211 werecreated. With the P-N junction implementation, SPNSSE 212 were created.

A 9V multimeter was used to verify that voltage supplied to theconductive material on the printed diode mylar sheet allowed current toflow through the printed diode, meaning the multimeter could measure thevaried resistance of the FSR material as it was compressed into thesemiconductor. When voltage was supplied to the conductive material onthe FSR material mylar sheet, no current could flow through the diodeand the resistance of the FSR material could not be measured.

The following U.S. patent applications are all incorporated by referenceherein: U.S. patent application Ser. No. 13/317,138; U.S. provisionalpatent application 61/686,472 filed Apr. 5, 2012 having attorney docketnumber KPER-16; U.S. provisional patent application 61/655,075 filedJun. 4, 2012 having attorney docket number KPER-17.

Although the invention has been described in detail in the foregoingembodiments for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the spiritand scope of the invention except as it may be described by thefollowing claims.

1. A sensor comprising: one or more printed mechanical sensing elementsthat detect mechanical forces applied to an element; one or more printeddiodes which are in contact with the one or more mechanical sensingelements and which control flow of electrical current to and from theone or more printed mechanical sensing elements; and a computer incommunication with the printed mechanical-sensing elements which causesprompting signals to be sent to the one or more printed mechanicalsensing elements and which reconstructs data signals received from theone or more printed mechanical-sensing elements through the one or moreprinted diodes.
 2. The sensor of claim 1 wherein the computer is incommunication with the one or more printed mechanical-sensing elementsby conductive material which causes the prompting signals to be sent tothe one or more printed mechanical sensing elements and whichreconstructs the data signals received by the conductive material fromthe one or more printed mechanical-sensing elements through the one ormore printed diodes.
 3. The sensor of claim 2 wherein the conductivematerial forms a grid that defines intersections, whereby eachintersection contains a printed mechanical sensing element in contactwith a printed diode.
 4. The sensor of claim 3 wherein each printedmechanical sensing element includes a force sensitive variable resistor.5. The sensor of claim 4 wherein each printed mechanical sensing elementincludes force sensitive resistive ink.
 6. The sensor of claim 5 whereinthe grid and the printed mechanical sensing elements and the printeddiodes form a mechanical sensing layer.
 7. A method for sensingcomprising: transmitting mechanical forces to one or more printedmechanical sensing elements; sending prompting signals associated withthe mechanical forces to a computer in communication with one or moreprinted diodes and the one or more printed mechanical sensing elements;and reconstructing with the computer the mechanical forces that wereapplied to the one or more printed mechanical sensing elements.
 8. Anapparatus for sensing comprising: a computer; and one or more printedelectronic diodes and printed mechanical sensing elements connected tothe computer, the one or more printed electronic diodes detectmechanical signals applied to the one or more mechanical-sensingelements and that provide corresponding values to the computer.